I have the same tank, and this is what I did in summary:
4 weeks to cycle the tank - left light off
Added 2 clowns - left light off for 3 months
Lights came on, and added zoas, torch, frogspawn, hammers, duncans in a span of 1-2 months.
I didn't really have to deal with any ugly phase - only a very minor touch of diatoms, and that was it. I left the lights off for 3 months, so that was what I think was key. No issues with any type of algae.
CUC: nassarius snails, astrea and trochus.
You have a very thick sandbed - any reason for that? You lose volume and as well can have issues with stuff developing deep down.
Are you using the stock light?
9 months in, the tank is completely fine - water parameters excellent, and I don't really have to manage it - just a 2 gallon water change every 2 weeks - not needed, but I do it anyways to replenish any trace elements. Every tank is different, and in my case yes, some might say I moved way way too fast, but my tank is living proof that it can be done.